quick version: take an plant oil producing crop corn, for instance:

1. extract the oil use the oil ==> biodiesel + glycerine use this glycerine to make ethanol

2. take the waste from the oil extraction process, to make ethanol

3. take the waste mash from #2 to feed yeast for an edible yeast based food product (for famine areas).

4. take the waste mush from #3, put it in a digester, and make methane gas for fuel.

From this, we have one source of biodiesel, 2 sources of ethanol, one source of methane, and a source of food to replace what was taken out of circulation.

I know there's something wrong with this whole scenario, but i don't know the chemistry involved. I welcome critiques explaining why this won't work chemically. Economically, it is probably dead in the water anyway.
-- copycat042, Aug 13 2008

I think this is good but i'm probably wrong.
I make soap myself and i know someone who makes biodiesel. We produce glycerine, which i don't bother to extract and he does. Glycerine, i.e. glycerol, is itself edible. It would be feasible to do this at step one, but maybe not desirable. Yeast eats sugar, not ethanol so far as i know - it's the waste product of yeast metabolism. However, there are organisms which make ethanoic acid from ethanol.
Each stage uses up some of the energy available, and this applies to the methane. The ethanol has to be a better fuel than the methane that would be produced, regardless of the energy density. Presumably this means there's less methane available from the waste.
However, what you _have_ got, i think, is this:

Stage one yields soap, biodiesel, glycerol/-ine, surfactants for other purposes. These are all good.

Ethanol gets you a good neutral solvent miscible with water and a fuel in itself, which makes me as a teetotal herbalist very happy, but you'd have to turn the glycerol into sugar first. You can then grow yeast on it having added something else, probably something from wee and sea water, or maybe compost.

From the ethanol, ethanoic acid and the bacteria which live off the ethanol to produce it are also available. Ethanoic acid is quite useful too, for example as a cleaning material, a solvent and to make batteries.

Stage four: Well, you do have some kind of sludge, and don't forget faeces, and you can doubtless make methane from it, but to do this biologically you'd do best to heat it, which would offset some of the energy available. Some of this heat can be derived from decomposition, but i don't think there'd be too much of it. You could use it as a fuel and it would be carbon neutral too, and you could also make halogenated compounds from it, driven maybe though they wouldn't be terribly marvellous environmentally. Acetylene is another option.

I'd say this is better as a source of raw materials than fuel or food.
-- nineteenthly, Aug 13 2008


i found a link (with google) where they were using a process to make alcohol from the glycerin by-product of biodiesel production. apparantly, there is a surplus of it on the market.

as far as the methane production, i was just trying to squeeze as much out of the available materials as possible.

i also saw a plant where they were pumping their waste CO2 through algae tanks to scrub some of the carbon. then they would use the algae to make biodiesel.
-- copycat042, Aug 13 2008


Yes, they also do that with combined heat and power plants and greenhouses, where they grow tomatoes.

I would currently pay just under six quid for a kilo of glycerine. This may not be the trade rate as i think the supply catalogue i just looked at is not, so it may be less. However, you have now motivated me to extract the glycerine from the soap i make and use it as a base for tinctures. It's not as good as ethanol but i wouldn't pay duty on it, which i have to do right now if i make an alcohol tincture. Interesting.

In a sense, the economics don't matter so much if all you're using to pay for it is your own labour, assuming you're underemployed like i am, and since you can get glycerine out of waste cooking oil, it would only cost as much as the energy, equipment and materials needed to extract it from soap, which i make from spent olive oil.
-- nineteenthly, Aug 13 2008


As an economy, these things are already as efficient as possible. Waste products are sold for the highest possible price or dumped.
-- Voice, Aug 14 2008


New uses for waste products can be found. This would potentially raise their price. Dumping doesn't necessarily mean it's lost because it's possible to rummage through bins and use, for example, the discarded wood, clothes and food you find. There's also the issue of use value versus exchange value. Dumping raises prices by creating scarcity. Just look round the back of any supermarket. Sell by dates have more than one purpose. The fruit out there could be fermented and distilled to make ethanol, then decomposed further to make ethanoic acid, for example.

There is a financial difference for me between having to buy vodka at six quid for three quarters of a litre and deriving glycerine from spent cooking oil effectively for free (i.e. i've already roasted with it).

There's a legal requirement to dispose of large quantities of cooking oil from restaurants and fast food places. These establishments will pay to have it taken away. People will then also pay you for biodiesel and you can also get free energy from it. This is a good thing for the people who can do it.

If i fish a few planks of wood out of a skip and proceed to burn it in the fireplace, this is also free energy.
-- nineteenthly, Aug 14 2008


Thats my point, nineteenthly, When such products exist in a diverse economy someone will see the opportunity and take advantage of it. When a whole project chain is being taken advantage of by a single organization it is known as a "verticle monopoly."
-- Voice, Aug 15 2008



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